STLX-2012

STLX-2012 is a biologic, Fc‑engineered monoclonal antibody targeting interleukin‑1 receptor accessory protein (IL1RAP), developed by Stelexis Therapeutics for hematologic malignancies such as chronic myelomonocytic leukemia, myelodysplastic syndromes, myelofibrosis, acute myeloid leukemia, systemic mastocytosis, and select solid tumors.[3][5][7][11] By binding IL1RAP, STLX-2012 blocks IL‑1 family cytokine signaling (including IL‑33 and IL‑36γ) and downstream phosphorylation of ERK, AKT, p38, and NF‑κB, and its Fc region incorporates DLE mutations (S239D, A330L, I332E) to enhance antibody‑dependent cellular cytotoxicity (ADCC) against IL1RAP‑expressing cancer cells.[3][5][12] In preclinical models, STLX-2012 reduces colony formation of primary AML samples and inhibits engraftment of AML patient cells in immunodeficient mice, and it has advanced into first‑in‑human evaluation with single intravenous dosing in healthy volunteers to characterize safety, pharmacokinetics, pharmacodynamics, and immunogenicity.[5][9]